Method for producing battery module

ABSTRACT

A method for producing a battery module is provided. The method for producing a battery module includes: stacking a plurality of battery cells; disposing a plurality of bus bars adjacent to electrode leads respectively provided at the plurality of battery cells; by a welding jig, pressing the electrode leads so that the electrode leads come into contact with the bus bars, respectively; and welding the electrode leads and the bus bars through an opening formed in the welding jig.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.16/346,021, filed on Apr. 29, 2019, which is a national phase entryunder 35 U.S.C. § 371 of International Patent Application No.PCT/KR2018/000360, filed on Jan. 8, 2018, published in Korean, whichclaims priority from Korean Patent Application No. 10-2017-0064794,filed on May 25, 2017, the disclosures of which are hereby incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to a method for producing the batterymodule, and more particularly, to a method for producing the batterymodule capable of coupling electrode leads to a bus bar without bendingthe electrode leads.

BACKGROUND ART

As technology development and demand for a mobile device have increased,demand for a secondary battery as an energy source has rapidlyincreased. Conventionally, a nickel-cadmium battery or a hydrogen ionbattery has been used as the secondary battery. However, a lithiumsecondary battery is recently widely used because charging anddischarging is free due to rare memory effect in comparison with anickel-based secondary battery, a self-discharge rate is very low, andan energy density is high.

The lithium secondary battery mainly uses a lithium oxide and acarbonaceous material as a positive electrode active material and anegative electrode active material, respectively. The lithium secondarybattery includes an electrode assembly in which a positive electrodeplate and a negative electrode plate, respectively coated with thepositive electrode active material and the negative electrode activematerial, are arranged with a separator therebetween, and an outermember, that is a battery case, which seals and receives the electrodeassembly together with an electrolyte solution.

The lithium secondary battery includes a positive electrode, a negativeelectrode, and a separator interposed therebetween and an electrolyte.Depending on which material is used for the positive electrode activematerial and the negative electrode active material, the lithiumsecondary battery is classified into a lithium ion battery (LIB) and apolymer lithium ion battery (PLIB). Generally, an electrode of thelithium secondary battery is prepared by applying the positive ornegative electrode active material to a current collector made ofaluminum or copper sheet, mesh, film, foil, or the like and then dryingthe same.

FIG. 1 is a diagram showing that an electrode lead and a bus barprovided in a conventional battery cell are electrically coupled to eachother. Referring to FIG. 1, in the conventional art, electrode leads 20respectively provided to a plurality of battery cells 10 are bent tocontact a surface of a bus bar 30, and then bonded thereto by welding40. In this case, a lot of manual works are demanded to a worker inorder to maintain a bending shape of the electrode leads 20, and theelectrode leads 20 and the bus bar 30 are not closely adhered to eachother due to an elastic recovery force of the electrode leads 20 made ofa metal. In addition, since the plurality of electrode leads 20 areoverlapped at one point of the bus bar 30 and then welded 40, theweldability is deteriorated.

DISCLOSURE Technical Problem

The present disclosure is directed to providing a method for producingthe battery module capable of closely adhering electrode leads and a busbar to each other by coupling the electrode leads to the bus bar withoutbending the electrode leads.

The present disclosure is also directed to providing a method forproducing the battery module capable of having improved weldabilitysince the electrode leads are not overlapped.

The present disclosure is also directed to providing a method forproducing the battery module capable of improving an automation ratio ofthe production line by eliminating a manual process for bending theelectrode leads.

Technical Solution

In one aspect of the present disclosure, there is provided a method forproducing a battery module, comprising: stacking a plurality of batterycells; disposing a plurality of bus bars adjacent to electrode leadsrespectively provided at the plurality of battery cells; by a weldingjig, pressing the electrode leads so that the electrode leads come intocontact with the bus bars, respectively; and welding the electrode leadsand the bus bars through an opening formed in the welding jig.

Also, the bus bar may have an inclined portion, and the electrode leadmay be welded at the inclined portion of the bus bar to be coupled tothe bus bar.

In addition, the bus bar may have an inclined portion and a horizontalportion horizontally extending from the inclined portion, and theelectrode lead may be welded at the horizontal portion of the bus bar tobe coupled to the bus bar.

Advantageous Effects

According to the embodiments of the present disclosure, since theelectrode leads may be coupled to each bus bar without being bent, theelectrode leads are not restored by an elastic recovery force, therebyallowing the electrode leads and the bus bar to be closely adhered.

Also, since the plurality of electrode leads are respectively coupled tothe plurality of bus bars, the electrode leads are not overlapped,thereby improving the weldability.

In addition, since a manual process for bending the electrode leads iseliminated, an automation ratio of the production line may be improved.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing that an electrode lead and a bus barprovided in a conventional battery cell are electrically coupled to eachother.

FIG. 2 is a schematic side sectioned view showing a state before anelectrode lead is coupled to a bus bar in a battery module according tothe first embodiment of the present disclosure.

FIG. 3 is a schematic side sectioned view showing a state after theelectrode lead is coupled to the bus bar in the battery module accordingto the first embodiment of the present disclosure.

FIGS. 4(a) to 4(d) are diagrams for illustrating a process that theelectrode lead is coupled to the bus bar in the battery module accordingto the first embodiment of the present disclosure.

FIGS. 5(a) to 5(d) are diagrams for illustrating a process that anelectrode lead is coupled to a bus bar in a battery module according tothe second embodiment of the present disclosure.

FIG. 6 is a schematic side sectioned view showing a state before anelectrode lead is coupled to a bus bar in a battery module according tothe third embodiment of the present disclosure.

FIG. 7 is a schematic side sectioned view showing a state after theelectrode lead is coupled to the bus bar in the battery module accordingto the third embodiment of the present disclosure.

FIGS. 8(a) to 8(c) are diagrams for illustrating a process that theelectrode lead is coupled to the bus bar in the battery module accordingto the third embodiment of the present disclosure.

BEST MODE

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. Priorto the description, it should be understood that the terms used in thespecification and the appended claims should not be construed as limitedto general and dictionary meanings, but interpreted based on themeanings and concepts corresponding to technical aspects of the presentdisclosure on the basis of the principle that the inventor is allowed todefine terms appropriately for the best explanation. Therefore, thedescription proposed herein is just a preferable example for the purposeof illustrations only, not intended to limit the scope of thedisclosure, so it should be understood that other equivalents andmodifications could be made thereto without departing from the scope ofthe disclosure.

In the drawings, the size of each element or a specific part of theelement may be exaggerated, omitted, or schematically illustrated forconvenience and clarity of a description. Thus, the size of each elementdoes not entirely reflect the actual size of the element. A detaileddescription of well-known functions or elements associated with thepresent disclosure will be omitted if it unnecessarily obscures thesubject matter of the present disclosure.

The term, ‘combine’ or ‘connect’ as used herein, may refer not only to acase where one member and another member are directly combined ordirectly connected but also a case where one member is indirectlycombined with another member via a connecting member or is indirectlyconnected.

FIG. 2 is a schematic side sectioned view showing a state before anelectrode lead is coupled to a bus bar in a battery module according tothe first embodiment of the present disclosure, and FIG. 3 is aschematic side sectioned view showing a state after the electrode leadis coupled to the bus bar in the battery module according to the firstembodiment of the present disclosure.

Referring to FIGS. 2 and 3, a battery module according to an embodimentof the present disclosure includes a battery cell stack 100 and aplurality of bus bars 200.

The battery cell stack 100 may be configured so that a plurality ofbattery cells 110 are stacked therein. The battery cells 110 may havevarious structures, and the plurality of unit cells 110 may be stackedin various ways. The battery cell 110 may be configured so that aplurality of unit cells, in each of which a positive electrode plate, aseparator and a negative electrode plate are arranged in order, or aplurality of bi-cells, in each of which a positive electrode plate, aseparator, a negative electrode plate, a separator, a positive electrodeplate, a separator and a negative electrode plate are arranged in order,are stacked suitable for a battery capacity.

The battery cell 110 may have an electrode lead 111. The electrode lead111 is a type of terminal that is exposed to the outside and connectedto an external device, and the electrode lead 111 may be made of aconductive material. The electrode lead 111 may include a positiveelectrode lead and a negative electrode lead. The positive electrodelead and the negative electrode lead may be disposed in oppositedirections with respect to the longitudinal direction of the batterycell 110, or the positive electrode lead and the negative electrode leadmay be positioned in the same direction with respect to the longitudinaldirection of the battery cell 110. The electrode lead 111 iselectrically coupled to the bus bar 200, explained later.

The battery cell stack 100 may include a plurality of cartridges (notshown) for accommodating the battery cells 110. Each cartridge (notshown) may be fabricated by injection-molding plastic, and a pluralityof cartridges (not shown) having an accommodation portion foraccommodating the battery cell 110 may be stacked. A cartridge assemblyin which a plurality of cartridges (not shown) are stacked may include aconnector element or a terminal element. The connector element mayinclude various types of electrical connecting components or connectingcomponents for connecting to, for example, a battery management system(BMS) (not shown) capable of providing data on voltage or temperature ofthe battery cells 110. In addition, the terminal element includes apositive electrode terminal and a negative electrode terminal as mainterminals connected to the battery cell 110, and the terminal elementmay have a terminal bolt to be electrically connected to the outside.Meanwhile, the battery cell 110 may have various shapes.

The bus bars 200 are coupled to the electrode leads 111 to electricallyconnect the electrode leads 111. Here, the electric connection mayinclude serial or parallel connection. The bus bars 200 are disposedadjacent to the electrode leads 111 to contact the electrode leads 111provided at the battery cells 110. Referring to FIG. 2, the bus bars 200may be disposed between the electrode leads 111. Here, at least one ofthe plurality of bus bars 200 may be disposed between neighboringelectrode leads 111, and the bus bar 200 disposed at an outermost sidemay be provided adjacent to a predetermined electrode lead 111. Inaddition, referring to FIG. 3, the electrode leads 111 respectivelyprovided at the plurality of battery cells 110 come into contact withand are electrically coupled to the plurality of bus bars 200,respectively.

The bus bar 200 may have various shapes, and, for example, as shown inFIGS. 2 and 3, an inclined portion 210 may be formed at the bus bar 200.In addition, the electrode lead 111 may have a first bent portion 115(see FIG. 3) bent at a slope corresponding to the inclination of theinclined portion 210. That is, the electrode lead 111 may be bent at thefirst bent portion 115 of the electrode lead 111, and then the electrodelead 111 may come into contact with the inclined portion 210 of the busbar 200. In addition, the electrode lead 111 may be welded 500 at theinclined portion 210 of the bus bar 200 to be coupled to the bus bar200. For this, a welding jig 300 with an inclination corresponding tothe inclined portion 210 of the bus bar 200 may press the electrode lead111 at an upper side of the electrode lead 111 to form the first bentportion 115 at the electrode lead 111. That is, if the welding jig 300presses the electrode leads 111, for example, downward at an upper sideof the electrode leads 111 after the plurality of bus bars 200 arerespectively disposed between the electrode leads 111 or adjacent to theelectrode leads 111, the electrode lead 111 are bent toward the inclinedportion 210 of the bus bar 200 to contact the inclined portion 210 ofthe bus bar 200. Here, an opening 330 may be formed in the welding jig300, and the welding 500, for example, laser welding, may be performedthrough the opening 330 of the welding jig 300 to electrically connectthe electrode leads 111 to the inclined portions 210 of the plurality ofbus bars 200, respectively. The welding jig 300 may include a bus barcontacting portion 310 contacting an upper side of the bus bar 200 and apressing bending portion 320 extending from the bus bar contactingportion 310 to press and bend the electrode lead 111. In addition, atthe welding jig 300, the opening 330 for the welding 500 may be providedin the pressing bending portion 320.

Hereinafter, the operation and effect of the battery module according tothe first embodiment of the present disclosure will be described withreference to the drawings.

FIGS. 4(a) to 4(d) are diagrams for illustrating a process that theelectrode lead is coupled to the bus bar in the battery module accordingto the first embodiment of the present disclosure. In FIGS. 4(a) to4(d), only a portion of FIG. 2, namely a portion A of FIG. 2, isdepicted.

Referring to FIG. 4(a), the bus bar 200 is disposed adjacent to theelectrode lead 111. Referring to FIG. 4(b), the welding jig 300 movesfrom an upper side to a lower side to press the electrode lead 111.Referring to FIG. 4(c), the electrode lead 111 is bent to contact theinclined portion 210 of the bus bar 200. Referring to FIG. 4(d), theelectrode lead 111 is electrically coupled to the inclined portion 210of the bus bar 200 through the opening 330 of the welding jig 300 bymeans of the welding 500, for example laser welding.

As a result, the electrode leads 111 and the bus bars 200 may be closelyadhered to each other and the electrode leads 111 may be respectivelycoupled to the bus bar 200 without bending the electrode leads 111,thereby preventing the electrode leads 111 from overlapping and thusimproving the welding property.

FIGS. 5(a) to 5(d) are diagrams for illustrating a process that anelectrode lead is coupled to a bus bar in a battery module according tothe second embodiment of the present disclosure.

Hereinafter, the function and effect of a battery module according tothe second embodiment according to the present disclosure will bedescribed with reference to the drawings, but features common to thebattery module according to the first embodiment of the presentdisclosure will not be described again in detail.

The second embodiment of the present disclosure is different from thefirst embodiment in the point that the electrode lead 111 is not weldedat the inclined portion 210 of the bus bar 200 but is welded at ahorizontal portion 220 of the bus bar 200.

Referring to FIGS. 5(a) to 5(d), the bus bar 200 may have a horizontalportion 220 extending horizontally from the inclined portion 210, inaddition to the inclined portion 210. In addition, a first bent portion115 and a second bent portion 116 are formed at the electrode lead 111.The first bent portion 115 may be formed in a way that the electrodelead 111 is bent at a slope corresponding to the inclination of theinclined portion 210 so that the electrode lead 111 comes into contactwith the inclined portion 210 of the bus bar 200, similar to the firstembodiment. In addition, the second bent portion 116 may be formed in away that the electrode lead 111 is bent to correspond to the horizontalportion 220 so that the electrode lead 111 may come into contact withthe horizontal portion 220 of the bus bar 200.

In addition, the electrode lead 111 may be welded 500 at the horizontalportion 220 of the bus bar 200 to be coupled to the bus bar 200, and theopening 330 for the welding 500 at the welding jig 300 may be providedin the bus bar contacting portion 310.

Referring to FIG. 5(a), the bus bar 200 is disposed adjacent to theelectrode lead 111. Referring to FIG. 5(b), the welding jig 300 is movedfrom an upper side to a lower side to press the electrode lead 111.Referring to FIG. 5(c), the electrode lead 111 is bent to come intocontact with the inclined portion 210 of the bus bar 200 and thehorizontal portion 220 of the bus bar 200. Referring to FIG. 5(d), theelectrode lead 111 is electrically coupled to the horizontal portion 220of the bus bar 200 through the opening 330 of the welding jig 300 bymeans of the welding 500, for example laser welding.

FIG. 6 is a schematic side sectioned view showing a state before anelectrode lead is coupled to a bus bar in a battery module according tothe third embodiment of the present disclosure, FIG. 7 is a schematicside sectioned view showing a state after the electrode lead is coupledto the bus bar in the battery module according to the third embodimentof the present disclosure, and FIGS. 8(a) to 8(c) are diagrams forillustrating a process that the electrode lead is coupled to the bus barin the battery module according to the third embodiment of the presentdisclosure. In FIGS. 8(a) to 8(c), only a portion of FIG. 6, namely aportion B of FIG. 6, is depicted.

Hereinafter, the function and effect of the battery module according tothe third embodiment according to the present disclosure will bedescribed with reference to the drawings, but features common to thebattery module according to the first and second embodiments of thepresent disclosure will not be described again in detail.

The third embodiment of the present disclosure is different from thefirst and second embodiments in the point that the electrode lead 111 iscoupled to the bus bar 200 not by welding but by an elastic member 400.

Referring to FIGS. 6 and 7, the elastic member 400 may be configured topress the electrode leads 111 so that the electrode leads 111 arecoupled to the plurality of bus bars 200, respectively. That is, sincethe electrode leads 111 are pressed by an elastic force of the elasticmember 400, the electrode leads 111 may be electrically coupled to thebus bars 200 without welding.

The elastic member 400 may have a variety of configurations, forexample, a leaf spring. The elastic member 400 may include a supportportion 410 and a pressing portion 420. The support portion 410 issupported in contact with the bus bar 200 at an upper side of the busbar 200. The support portion 410 may be in contact with, for example,the horizontal portion 220 of the bus bar 200. The pressing portion 420may be configured to extend from the support portion 410 and press theelectrode lead 111 while moving, for example, from an upper side to alower side of the electrode lead 111. The pressing portion 420 may beprovided in plural corresponding to the number of the electrode leads111. In the first and second embodiments, the welding jig 300 is removedafter the electrode lead 111 and the bus bar 200 are coupled. However,in the third embodiment, the elastic member 400 is inserted between thebus bars 200 and maintained so that the electrode leads 111 are incontact with the bus bars 200.

Referring to FIGS. 6 and 7, similar to the first and second embodiments,the bus bar 200 may have an inclined portion 210 formed therein, and theelastic member 400 presses the electrode leads 111 so that the electrodeleads 111 are coupled to the inclined portions 210 of the plurality ofbus bars 200, respectively. However, the elastic member 400 may alsopress the electrode leads 111 so that the electrode leads 111 contactboth the inclined portion 210 and the horizontal portion 220 of the busbar 200, without being limited to the above.

Referring to FIG. 8(a), the bus bar 200 is disposed adjacent to theelectrode lead 111. Referring to FIG. 8(b), the elastic member 400presses the electrode lead 111 while moving from an upper side to alower side. Referring to FIG. 8(c), the electrode lead 111 comes intocontact with the inclined portion 210 of the bus bar 200 and iselectrically connected thereto by the elastic member 400.

Meanwhile, a battery pack (not shown) according to an embodiment of thepresent disclosure may include one or more battery modules according toan embodiment of the present disclosure as described above. Also, inaddition to the battery modules, the battery pack (not shown) mayfurther includes a case for accommodating the battery modules, andvarious devices for controlling charge and discharge of the batterymodules, such as a BMS, a current sensor, a fuse, and the like.

Meanwhile, a vehicle (not shown) according to an embodiment of thepresent disclosure may include the battery module or the battery pack(not shown) described above, and the battery pack (not shown) mayinclude the battery module. In addition, the battery module according toan embodiment of the present disclosure may be applied to the vehicle(not shown), for example, a predetermined vehicle (not shown) providedto use electricity like an electric vehicle or a hybrid electricvehicle.

Hereinafter, a method of producing a battery module according to anembodiment of the present disclosure will be described with reference tothe drawings.

First, a plurality of battery cells 110 are stacked to form a batterycell stack 100. The number of battery cells 110 is not limited. Inaddition, a plurality of bus bars 200 are disposed adjacent to electrodeleads 111 respectively provided at the plurality of battery cells 110,respectively. Here, the bus bar 200 may be disposed between neighboringelectrode leads 111. In addition, the welding jig 300 presses theelectrode leads 111 while moving, for example, from an upper side to alower side of the electrode leads 111 so that the electrode leads 111come into contact with the respective bus bars 200. Here, the pressingbending portion 320 of the welding jig 300 may press the electrode lead111. In addition, the electrode leads 111 and the bus bars 200 arewelded 500, for example laser-welded, through the opening 330 formed inthe welding jig 300, thereby electrically coupling the electrode leads111 and the bus bars 200.

In addition, an inclined portion 210 may be formed at the bus bar 200,and the electrode lead 111 may be welded 500 at an inclined portion 210of the bus bar 200 to be coupled to the bus bar 200 after being bent bythe welding jig 300. Alternatively, the bus bar 200 may have an inclinedportion 210 and a horizontal portion 220 extending horizontally from theinclined portion 210, and the electrode lead 111 may be bent by thewelding jig 300 and then welded 500 at the horizontal portion 220 of thebus bar 200 to be coupled to the bus bar 200.

The present disclosure has been described in detail. However, it shouldbe understood that the detailed description and specific examples, whileindicating preferred embodiments of the disclosure, are given by way ofillustration only, since various changes and modifications within thescope of the disclosure will become apparent to those skilled in the artfrom this detailed description.

INDUSTRIAL APPLICABILITY

The present disclosure is directed to a battery module, a battery packincluding the battery module, and a method for producing the batterymodule, and is particularly applicable to industries associated with asecondary battery.

What is claimed is:
 1. A method for producing a battery module,comprising: stacking a plurality of battery cells; disposing a pluralityof bus bars adjacent to electrode leads respectively provided at theplurality of battery cells; by a welding jig, pressing the electrodeleads so that the electrode leads come into contact with the bus bars,respectively; and welding the electrode leads and the bus bars throughan opening formed in the welding jig.
 2. The method for producing abattery module according to claim 1, wherein the bus bar has an inclinedportion, and the electrode lead is welded at the inclined portion of thebus bar to be coupled to the bus bar.
 3. The method for producing abattery module according to claim 1, wherein the bus bar has an inclinedportion and a horizontal portion horizontally extending from theinclined portion, and the electrode lead is welded at the horizontalportion of the bus bar to be coupled to the bus bar.